Electro-active diffractive lens and method for making the same

ABSTRACT

Aspects of the present invention provide an electro-active lens and method for manufacturing the same that encapsulates liquid crystal using solid transparent optical material using an improved liquid crystal seal feature. The seal feature greatly reduces the visibility of the liquid crystal seal feature in an assembled electro-active lens. The seal feature is also structurally robust such that the electro-active lens can be processed to fit a spectacle frame without disturbing containment of the liquid crystal and without disrupting electrical connectivity to the lens used to alter the refractive index of the liquid crystal, thereby ensuring fabrication of a commercially viable electro-active lens.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/959,501, filed Aug. 5, 2013, which is hereby incorporated byreference in its entirety. U.S. patent application Ser. No. 13/959,501is a divisional of U.S. patent application Ser. No. 12/408,973 filedMar. 23, 2009, now U.S. Pat. No. 8,523,354, which is hereby incorporatedby reference in its entirety. The present application also claimsbenefit of priority to the following U.S. Provisional patentapplications via U.S. patent application Ser. No. 12/408,973. U.S. Appl.No. 61/044,205, filed on Apr. 11, 2008; and U.S. Appl. No. 61/152,913,filed on Feb. 16, 2009. Each of these applications is herebyincorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to lenses. More specifically,the present invention provides encapsulation of a liquid opticalmaterial using a solid optical material with improved structuralintegrity and reduced visibility of any liquid optical material sealfeature.

2. Background Art

Electro-active lenses generally include a liquid optical material (e.g.,liquid crystal) encapsulated or contained by one or more solid,transparent optical materials. Conventional methods and structures forcontaining the liquid optical material often result in a visible sealring on the lens indicating the positioning of the liquid opticalmaterial. These visible seal rings are cosmetically undesirable toconsumers.

In conventional liquid crystal displays (LCDs), sealing features cantypically be hidden behind an opaque frame or bezel. Such structures,however, are not viable for ophthalmic lenses and spectacle lenses inparticular.

To date, methods and structures designed to reduce the visibility of anyliquid optical material seal in an ophthalmic lens often compromise thestructural integrity of the lens. As such, conventional methods forprocessing such lenses (e.g., conventional methods for cutting andedging a lens) can cause containment of the liquid optical material tobe disturbed and can also disrupt the ability to alter the refractiveindex of the liquid optical material electronically. Consequently, manyprior art electro-active lenses are not commercially viable products.

Accordingly, what is needed is an electro-active lens and method formanufacturing the same that encapsulates liquid crystal using solidtransparent optical material such that the visibility of any liquidcrystal seal feature is substantially reduced, while simultaneouslyproviding a structurally robust lens that can be processed to fit aspectacle frame without disrupting containment of the liquid crystal orthe ability to alter its refractive index electronically.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

FIG. 1 illustrates an electro-active semi-finished lens blank (EASFLB)in accordance with an aspect of the present invention.

FIG. 2 illustrates an exploded cross-sectional view of the EASFLBdepicted in FIG. 1.

FIG. 3 illustrates a side view of the EASFLB depicted in FIG. 1.

FIG. 4 illustrates a close-up view of a cross section of the EASFLBdepicted in FIG. 3 along a radial direction.

FIG. 5 provides a flowchart that illustrates operational steps formanufacturing the EASFLB in accordance with an aspect of the presentinvention.

FIG. 6 provides a flowchart that illustrates operational steps forgenerating a front substrate of the EASFLB in accordance with an aspectof the present invention.

FIG. 7 provides a flowchart that illustrates operational steps forgenerating a back substrate of the EASFLB in accordance with an aspectof the present invention.

FIG. 8 provides a flowchart that illustrates operational steps forcleaning and annealing the front substrate and the back substrate of theEASFLB in accordance with an aspect of the present invention.

FIG. 9 provides a flowchart that illustrates operational steps forapplying multiple layers to the front and back substrates of the EASFLBto form a portion of a dynamic, electro-active, diffractive opticalpower region in accordance with an aspect of the present invention.

FIGS. 10A and 10B illustrate an exemplary deposition of conductivelayers of the EASFLB in accordance with an aspect of the presentinvention.

FIG. 11 provides a flowchart that illustrates operational steps forapplying an adhesion promoter to substrates of the EASFLB in accordancewith an aspect of the present invention.

FIG. 12 provides a flowchart that illustrates operational steps forapplying alignment layers to substrates of the EASFLB in accordance withan aspect of the present invention.

FIG. 13 provides a flowchart that illustrates operational steps forformulating electro-active material in accordance with an aspect of thepresent invention.

FIGS. 14A-D illustrate an exemplary process for aligning a frontsubstrate and a back substrate of the EASFLB.

FIGS. 15A-D illustrate an exemplary carrier for holding a substrate ofthe EASFLB.

FIG. 16 provides a flowchart that illustrates operational steps forexposing alignment layers of substrates of the EASFLB to ultra-violetlight in accordance with an aspect of the present invention.

FIG. 17 provides a flowchart that illustrates operational steps forassembling front and back substrates to form the EASFLB in accordancewith an aspect of the present invention.

FIGS. 18A-C illustrate dispensing and encapsulating electro-activematerial within the EASFLB in accordance with an aspect of the presentinvention.

FIG. 19 illustrates a radius of curvature of a front substrate of theEASFLB in accordance with an aspect of the present invention.

FIGS. 20A-C illustrate introduction and curing of an adhesive to adherefront and back substrates of the EASFLB in accordance with an aspect ofthe present invention.

FIG. 21 illustrates a first exemplary alternative EASFLB in accordancewith an aspect of the present invention.

FIG. 22 illustrates a second exemplary alternative EASFLB in accordancewith an aspect of the present invention.

FIG. 23 illustrates a third exemplary alternative EASFLB in accordancewith an aspect of the present invention.

FIG. 24 provides a flowchart that illustrates operational steps forfinal processing the EASFLB in accordance with an aspect of the presentinvention.

FIG. 25 illustrates an exemplary placement of a new peripheral edge ofan EASFLB in accordance with an aspect of the present invention.

FIGS. 26A and 26B illustrate an EASFLB processed to have a reduceddiameter in accordance with an aspect of the present invention.

FIG. 27 illustrates a top view of an edged spectacle lens that can beformed from a cribbed, surfaced, and coated EASFLB in accordance with anaspect of the present invention.

FIG. 28 illustrates a finished and edged spectacle lens in accordancewith an aspect of the present invention

FIG. 29 illustrates a portion of the dynamic, electro-active,diffractive optical power region of the EASFLB in accordance with anaspect of the present invention.

FIGS. 30A-C illustrate exemplary surface relief diffractive structuresin accordance with an aspect of the present invention.

FIGS. 31A-B illustrate additional exemplary surface relief diffractivestructures in accordance with an aspect of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the present invention provide an electro-active lens andmethod for manufacturing the same that encapsulates liquid crystal usingsolid transparent optical material using an improved liquid crystal sealfeature. The seal feature greatly reduces the visibility of the liquidcrystal seal feature in an assembled electro-active lens. The sealfeature is also structurally robust such that the electro-active lenscan be processed to fit a spectacle frame without disturbing containmentof the liquid crystal and without disrupting the electrical connectivityto the lens used to alter the refractive index of the liquid crystal,thereby ensuring fabrication of a commercially viable electro-activelens.

As used herein, an electro-active lens can be an unfinished lens blank,a semi-finished lens blank, a finished lens blank, an edged lens, acontact lens, an intra-ocular lens, a corneal inlay or a corneal onlay.

FIG. 1 illustrates an electro-active semi-finished lens blank (EASFLB)100 in accordance with an aspect of the present invention. The EASFLB100 can comprise a first substrate (e.g., a top substrate) and a secondsubstrate (e.g., a bottom substrate). FIG. 1 depicts a top view of theEASFLB 100. Accordingly, FIG. 1 shows a view of the top substrate of theEASFLB 100.

As depicted in FIG. 1, the EASFLB 100 can comprise a progressiveaddition optical power region 101 in optical communication with adynamic, electro-active, diffractive optical power region 102. Thedynamic, electro-active, diffractive optical power region 102 cancomprises an electro-active material such as, for example, a cholestericliquid crystalline (CLC) material. The electro-active material can beencapsulated within a volume by the two bounding substrates (i.e., thetop and bottom substrates of the EASFLB 100) and an electro-activematerial seal feature 103.

The dynamic, electro-active, diffractive optical power region 102 isshown as having an oval shape but is not so limited. The dynamic,electro-active, diffractive optical power region 102 can be of any shape(e.g., round, flat-topped, semi-circle, etc.) and can be blended asdescribed in U.S. patent application Ser. No. 12/166,526, filed Jul. 2,2008, which is hereby incorporated by reference in its entirety.

FIG. 1 shows the progressive addition optical power region 101overlapping or positioned within a boundary defined by the dynamic,electro-active, diffractive optical power region 102 for purposes ofillustration only. The positioning of the progressive addition opticalpower region 101, however, is not so limited. Overall, the progressiveaddition optical power region 101 and the dynamic, electro-active,diffractive optical power region 102 can be positioned in anyorientation with respect to one another. To that end, any or allportions of the progressive addition optical power region 101 canoverlap any or all portions of the dynamic, electro-active, diffractiveoptical power region 102. This enables the progressive addition opticalpower region 101 to extend beyond the boundary defined by the dynamic,electro-active, diffractive optical power region 102 while stilloverlapping a substantial portion of the dynamic, electro-active,diffractive optical power region 102.

An adhesive can adhere the two substrates of the EASFLB 100 together andcan be applied via one or more fill ports 104. The adhesive can becontained in a volume determined by the bounding substrates of theEASFLB 100 (i.e., the top and bottom substrates), the electro-activematerial seal feature 103 and an adhesive seal feature 105. Therefractive index of the adhesive can be substantially equal to therefractive indices of one or more of the bounding substrates of theEASFLB 100. The adhesive seal feature 105 can be located towards theperiphery of the EASFLB 100. The electro-active material seal feature103 can be considered to be an electro-active material seal structure103. Similarly, the adhesive seal feature 105 can be considered to be anadhesive seal structure 105.

Electrical contacts 106 and 107 can allow a voltage to be applied to thedynamic, electro-active, diffractive optical power region 102 so as toallow activation of the dynamic, electro-active, diffractive opticalpower region 102. Electrical contact can be made between the electricalcontacts 106 and 107 and the dynamic, electro-active, diffractiveoptical power region 102 via transparent conductors. The electricalcontacts 106 and 107 can be applied to the inner surfaces of the twobounding substrates and can therefore be embedded within the EASFLB 100.As shown in FIG. 1, the electrical contacts 106 and 107 are positionedwithin a boundary defined by the adhesive seal feature 105 but are notso limited.

Semi-visible fiducial marks 108 and 109 can be included on and/or in theEASFLB 100 to act as guiding or alignment marks during manufacture ofthe EASFLB 100 (i.e., to aid in manufacturing the EASFLB 100). Thesemi-visible fiducial marks 108 and 109 can be located on the anteriorsurfaces of the bounding substrates for example.

An exploded cross-sectional view of the EASFLB 100 (not to scale) isshown in FIG. 2. The EASFLB 100 can be constructed from theaforementioned bounding substrates—in particular, a back substrate 201and a front substrate 202. The back substrate 201 can be thicker thanthe front substrate 202. The back substrate 201 can comprise any lensmaterial. As an example, the back substrate 201 can comprise a materialhaving a refractive index of 1.67 such as Mitsui MR-10. The frontsubstrate 202 can also comprise any lens material. As an example, thefront substrate 202 can comprise the same lens material as the backsubstrate 201 (e.g., the front substrate 202 can comprise MR-10material). Alternatively, the front substrate 202 can comprise adifferent lens material (e.g., the back substrate 201 can compriseTrivex® having a refractive index of 1.53. As will be appreciated by oneskilled in the relevant arts, the features and characteristics of thefront substrate 202 and the back substrate 201 can be interchanged inaccordance with an aspect of the present invention.

The front substrate 202 and the back substrate 201 can have any desiredthickness. As an example, the thickness of the back substrate 201 can bebetween 5.0 mm and 10.0 mm while the thickness of the front substrate202 can be between 0.5 mm and 2.0 mm. The anterior, convex surface ofthe back substrate 201 can contain the electro-active material sealfeature 103, the adhesive seal feature 105, and a surface reliefdiffractive structure 213.

The surface relief diffractive structure 213, when in physical andoptical communication with an electro-active material, can be designedto generate a phase retardation of m2π, where m is an integer. Inaccordance with an aspect of the present invention, m can be equal toone (1). For large values of m (e.g., m>5), chromatic aberration may bereduced and the surface relief diffractive structure 213 may becharacterized as a multi-order surface relief diffractive structure.Accordingly, the surface relief diffractive structure 213 can beimplemented as a multi-order surface relief diffractive structure asdescribed in U.S. patent application Ser. No. 12/118,226, filed on May9, 2008, which is hereby incorporated by reference in its entirety.

The anterior, convex surface of back substrate 201 can also compriseadditional semi-visible fiducial marks 109 (shown in FIG. 1) for thepurpose of aiding the manufacturing process. The posterior, concavesurface of the back substrate 201 can be substantially featureless.After assembly of the EASFLB 100, the posterior, concave surface of theback substrate 201 can be further processed to form a final ophthalmiclens for a patient. For example, the posterior, concave surface of theback substrate 201 can be edged, cut and/or free-formed in accordancewith a patient's vision prescription. In particular, a progressiveaddition optical power region can be free-formed onto the posterior,concave surface of the back substrate 201. This can obviate generation(e.g., either by mold or by free-forming) of the progressive additionoptical power region 101 on the front substrate 202. Alternatively, aprogressive addition optical power region can be formed on both thefront substrate 202 and the back substrate 201 (e.g., either by mold orby free-forming). This can allow the progressive addition optical powerregion 101 to be of a lower power design, thereby lowering the totalamount of unwanted astigmatism introduced by the progressive additionoptical power regions of the EASFLB 100.

The anterior, convex surface of the front substrate 202 can comprise theprogressive optical power region 101 and the semi-visible fiducial marks108 (both shown in FIG. 1) while the concave surface of the frontsubstrate 202 can be substantially featureless. The front substrate 202can also comprise the adhesive fill ports 104. The adhesive fill ports104 can be through-holes that are between 1.0 min and 2.0 mm indiameter. The adhesive fill ports 104 can be drilled or machined intothe front substrate 202 or can be formed by other suitable means (e.g.,by mold). Alternatively or in addition thereto, the back substrate 201can comprise the adhesive fill ports 104.

The edge of the back substrate 201 can contain a bevel 215 to aid in thehandling of the back substrate 201 during manufacture and assembly ofthe EASFLB 100. The edge of the front substrate 202 can also contain abevel 214 to aid in the handling of the front substrate 202 duringmanufacture and assembly of the EASFLB 100.

Additional layers and structures can be applied to the convex surface ofthe back substrate 201 and to the concave surface of the front substrate202 to allow operation of the dynamic, electro-active, diffractiveoptical power region 102. First layers 203 and 204 can any transparentmaterial that is electrically insulating. As an example, the layers 203and 204 can comprise SiO_(x) (e.g., SiO₂ or SiO₃). Each of the layers203 and 204 can have a thickness of 20 nm for example.

On top of each of the layers 203 and 204, a conductive material can bepatterned into fine wires to form the electrical contacts 106 and 107.On top of the electrical contacts 106 and 107, transparent conductorlayers 205 and 206 can be deposited. Each of the transparent conductorlayers 205 and 206 can comprise a transparent conductive material suchas Indium Tin Oxide (ITO) or Zinc Oxide (ZnO). The transparent conductorlayers 205 and 206 can have a thickness of 20 nm for example. Thetransparent conductor layers 205 and 206 can be in electrical contactwith the corresponding electrical contacts 106 and 107. The electricalcontacts 106 and 107 can provide electrical contact to the dynamic,electro-active, diffractive optical power region 102 through the edge ofthe EASFLB 100.

One or more of the transparent conductor layers 106 and 107 can bedeposited or formed to be patterned electrode structures (or pixelatedstructures) as described in U.S. patent application Ser. No. 12/246,543,filed on Oct. 7, 2008 and U.S. patent application Ser. No. 12/135,587,filed on Jun. 9, 2008, both of which are hereby ‘incorporated byreference in their entirety. Such a patterned electrode structure can beused to form a desired diffractive pattern using a volume ofelectro-active material (e.g., electro-active material 211 contained ina space that need not rest on top of a diffractive relief structure).

On top of the transparent conductor layers 205 and 206, insulatinglayers 207 and 208 can be deposited. The insulating layers 207 and 208can comprise any transparent material that is electrically insulating.As an example, the layers 207 and 208 can comprise SiO_(x) (e.g.,similar to the first layers 203 and 204). The insulating layers 207 and208 can comprise 170 nm of SiO_(x) for example. The final layersdeposited can comprise liquid crystal alignment material layers 209 and210 which act to align a volume of electro-active material 211encapsulated within the EASFLB 100. The arrangement and thicknesses ofthe layers 203-210 maximizes luminous transmittance through the EASFLB100 while minimizing electrical power consumption of the dynamic,electro-active, diffractive optical power region 102.

The surface relief diffractive structure 213, the electro-activematerial seal feature 103, and the layers and elements 203-211 can beconsidered to be an electro-active element of the EASFLB 100 (e.g., thedynamic, electro-active, diffractive optical power region 102). Any ofthe layers and elements 203-211 can be deposited across an entire areaof the EASFLB 100 (e.g., the insulating layers 203 and 204) or can bedeposited over less than an entire area of the EASFLB 100 or a portionof the entire area of the EASFLB 100 (e.g., the alignment layers 209 and210). Further, the surface relief diffractive structure 213 and theelectro-active material seal feature 103 can occupy any portion of theanterior, convex surface of the back substrate 201. Additionally, aswill be appreciated by one skilled in the relevant arts, the surfacerelief diffractive structure (and associated electro-active materialseal feature and adhesive seal feature for example) of the EASFLB 100can be alternatively positioned on the front substrate 202.

As shown in FIG. 2, the dynamic, electro-active, diffractive opticalpower region 102 is shown as comprising multiple layers and elements ofthe EASFLB 100. Further, the dynamic, electro-active, diffractiveoptical power region 102 is shown as occupying a portion of an entirehorizontal width of the EASFLB 100. As described further below, theEASFLB 100 can be further processed to form a finished lens blank or anedged lens (ready to be mounted into a spectacle frame). Overall, thearrangement of the layers of the EASFLB 100 can be varied as will beunderstood by one skilled in the relevant arts and as described in U.S.patent application Ser. No. 12/042,643, filed on Mar. 3, 2008, which ishereby incorporated by reference in its entirety.

Additionally, as shown in FIGS. 1 and 2, the electro-active materialseal structure 103 can be positioned around the surface reliefdiffractive structure 213. That is, the electro-active material sealstructure 103 can surround or enclose the surface relief diffractivestructure 213. Further, the electro-active material seal structure 103can be formed to sit higher than the surface relief diffractivestructure 213. The electro-active material seal structure 103 can beformed at the same time as forming the back substrate 201 or can beadded to the back substrate 201 after formation of the surface reliefdiffractive structure 213.

As indicated in FIGS. 1 and 2, the electro-active material sealstructure 103 can contain or encapsulate the electro-active material 211(e.g., over the surface relief diffractive structure 213). Further, theelectro-active material seal structure 103 can ensure the electro-activematerial 211 remains isolated from any adhesive positioned between theelectro-active material seal structure 103 and the adhesive sealstructure 105. Lastly, the electro-active material seal structure 103can be positioned so that portions of the EASFLB 100 can be subsequentlyremoved (e.g., portions between the electro-active material sealstructure 103 and the periphery of the EASFLB 100) without disturbingcontainment of the electro-active material 211 (e.g., leakage of theelectro-active material 211).

The adhesive structure 105 can be positioned towards the edge of theback substrate 201. The adhesive seal structure 105 can be formed at thesame time as forming the back substrate 201 or can be added to the backsubstrate 201 at a later time. The electro-active material sealstructure 103 and the adhesive seal structure 105 can comprise the samematerial as the back substrate 201 or can comprise a different material.

To form the EASFLB 100, the two substrates 201 and 202 can be broughtinto physical contact as shown in FIG. 3. The convex surface of the backsubstrate 201 can come into contact with the concave surface of thefront substrate 202 only along the electro-active material seal feature103 and the adhesive seal feature 105, thus encapsulating the volume ofelectro-active material 211 and forming an adhesive cavity 301. Uncuredliquid adhesive can then be introduced into the adhesive cavity 301through one or more fill ports 104. The liquid adhesive can then becured to a solid state, adhering the two substrates together andpermanently encapsulating the volume of electro-active material 211within the EASFLB 100.

As shown in FIG. 3, the electro-active material seal structure 103 canensure the electro-active material 211 remains contained so that it doesnot leak into the adhesive cavity 301. That is, the electro-activematerial seal structure 103 can isolate or separate the electro-activematerial 211 from the adhesive cavity 301 (and any adhesive subsequentlyplaced in the adhesive cavity 301).

FIG. 4 illustrates a close-up view of a cross section of the EASFLB 100article along a radial direction. FIG. 4 shows an example of how thevolume of electro-active material 211 can be encapsulated. As shown, theback substrate 201 can comprise a surface relief diffractive structure213. The surface relief diffractive structure 213 can have a maximumdepth. The maximum depth of the surface relief diffractive structure 213can be, for example, approximately 3.3 μm. The surface reliefdiffractive structure 213 can sit atop a mesa structure 302. The mesastructure 302 can have a height of approximately 40 μm for example. Themesa structure 302, along with the adhesive seal feature 105, can formthe adhesive cavity 301. The adhesive cavity 301 can be of sufficientdepth to allow uncured liquid adhesive to flow unencumbered by excessivecapillary forces.

The electro-active material seal feature 103 can be positioned proud ofthe peaks of the surface relief diffractive structure 213. As anexample, the electro-active material seal feature 103 can be positionedproud of the peaks of the surface relief diffractive structure 213 byapproximately 0.4 μm (400 nm). The electro-active material seal feature103 can be positioned to be at the same relative height from the outer,anterior, convex surface 303 of the back substrate 201 as the adhesiveseal feature 105. This can allow the posterior, concave, surface 304 ofthe front substrate 202 to only contact the back substrate 201 at theapex points of the electro-active material seal feature 103 and theadhesive seal feature 105. By allowing the two substrates to come intocontact in this manner, the volume of electro-active material 211 can besegregated from the uncured liquid adhesive by means of theelectro-active material seal feature 103. Further, uncured liquidadhesive may be contained within the adhesive cavity 301 by means of theelectro-active material seal feature 103 and the adhesive seal feature105.

In the following, a detailed description of the process formanufacturing the EASFLB 100 is provided.

FIG. 5 provides a flowchart 500 that illustrates operational steps formanufacturing the EASFLB 100 in accordance with an aspect of the presentinvention. The invention is not limited to this operational description.Rather, it will be apparent to persons skilled in the relevant art(s)from the teachings herein that other operational control flows arewithin the scope and spirit of the present invention. In the followingdiscussion, the steps in FIG. 5 are described.

FIG. 5 breaks down the entire manufacturing process into major steps 501through 509. The first step 501 comprises casting, edging, and drillingthe two substrates of the EASFLB 100—i.e., the top substrate 202 and thebottom substrate 201. FIG. 6 provides a flowchart 600 that illustratesoperational steps for generating the front substrate 202 that is shownmore generally as step 501 in FIG. 5. The front substrate 202 can beformed according to any known substrate fabrication processes as will beunderstood by one skilled in the relevant arts. Accordingly, FIG. 6illustrates an exemplary process.

As shown in FIG. 6, the process begins with step 601, which comprisesselecting a concave mold for creating the progressive addition opticalpower region 101. The concave mold for creating the progressive additionoptical power region 101 can comprise a region of substantially constantcurvature and one or more regions of smoothly varying curvature. Step601 can also comprise selecting a corresponding convex mold withsubstantially constant curvature. As is well known in the spectacle lensart, the substantially constant curvatures may be spherical, aspheric orany combination thereof.

At step 602, the selected molds are assembled into a mold cavity usingeither tape or a pre-fabricated gasket. The selected concave and convexmold assembly can generate a front substrate 202 having a substantiallyconstant thickness. The thickness of the front substrate 202 can be, forexample, between 0.5 mm and 2.0 mm. At step 603, a liquid resin is mixedfrom monomers and/or other precursor materials. The resin can be anyresin material.

At step 604, the prepared liquid resin is filled into the mold cavity.At step 605, the liquid resin is cured (polymerized) to form a solid.The resin can be a monomer that, when cured, generates a solid materialhaving a refractive index of 1.67 (e.g., Mitsui MR-10) for example. Theresin can be cured (polymerized) by using heat, light, or anycombination thereof. The front substrate 202 can also alternatively beformed by injection molding.

After the resin cure cycle 605, at step 606, the cast part is de-moldedand the selected molds can be cleaned for casting subsequent parts. Atstep 607, the cast part can be thermally annealed under vacuum at atemperature below the glass transition temperature of the cured resin toprepare it to receive an anti-scratch coating. At step 608, ananti-scratch-coating can be applied to the front substrate 202. Theanti-scratch coating applied to the front substrate 202 can be, forexample, HI-GARD™ 1080. Any anti-scratch coating can be applied byeither dip coating or spin coating. After application of theanti-scratch coating in step 608, the part can be edged to apre-determined diameter at step 609. At step 610, the fill ports 104 canbe added.

The progressive addition optical power region 101 can be aligned asdesired with respect to the dynamic, electro-active, diffractive opticalpower region 102. A desired alignment can be facilitated by edging thefront substrate 202 such that the position of the progressive additionoptical power region 101 is held to an acceptable tolerance (e.g., ±0.25mm) with respect to the outer edge of the substrate 202. Alternatively,or in addition thereto, alignment can be achieved optically (e.g., usingconventional optical alignment mechanisms) using semi-visible alignmentmarks on each substrate. During the edging process the bevel structure214 can be added. The bevel 214 can be v-shaped and can facilitate themounting of the substrate 202 in various process tooling (e.g., duringsubsequent steps). An acceptable or desired tolerance can be achieved byprocessing the substrate 202 using, for example, commercially availableComputer Numerically Controlled (CNC) spectacle lens blocking and edgingequipment. The fill ports 104 can be machined by most CNC spectacle lensedging machines but can also be created by any appropriate drilling ormachining means.

FIG. 7 provides a flowchart 700 that illustrates operational steps forgenerating the back substrate 201 that is shown more generally as step501 in FIG. 5. The back substrate 201 can be formed according to anyknown substrate fabrication processes as will be understood by oneskilled in the relevant arts. Accordingly, FIG. 7 illustrates anexemplary process.

At step 701, a concave front diffractive mold and a convex back mold canbe selected. A mold used for creating the surface relief diffractivestructure 213, the CLC seal feature 103, and the adhesive seal feature105 (and possibly semi-visible fiducials 109) can be fabricated inaccordance with those techniques described in U.S. patent applicationSer. No. 12/166,526, filed Jul. 2, 2008, which is hereby incorporated byreference in its entirety. For example, each of the surface reliefdiffractive structure 213, the electro-active material seal feature 103,and the adhesive seal feature 105, or any combination thereof, can becut into a Ni plated tooling master using precision single-point diamondturning techniques.

From a master tool fabricated in this manner, replicas can be made usinga Ni electro-forming process. These replica molds can then be used asmolds for casting substrates having the surface relief diffractivestructure 213, the electro-active material seal feature 103 and/or theadhesive seal feature 105, or any combination thereof. The selectedconvex back mold can be a conventional glass mold.

At step 702, the selected front mold can be assembled into a mold cavitywith the selected back mold using either tape or a pre-fabricatedgasket. The molds can be arranged so as to form the back substrate 201with a substantially constant thickness. For example, the molds can bearranged to form the back substrate 201 to have a thickness between 5.0mm and 10.0 mm. The curvatures of the molds used to form the backsubstrate 201 can be spherical, aspheric or a combination thereof.

At step 703, a liquid resin can be mixed from monomers and/or otherprecursor materials. At step 704, the resin can be used to fill the moldcavity. At step 705, the resin can be cured (e.g., polymerized) to forma solid. The monomer resin can be any resin. As an example, the resincan be a material that when cured generates a solid material having arefractive index of approximately 1.67 (e.g., Mitsui MR-10). Further,the solid material formed by curing the resin can have a refractiveindex that substantially matches the effective refractive index of theelectro-active material 211 when no electrical power is applied. Theresin can be cured (polymerized) by using heat, light, or anycombination thereof. The back substrate 201 can also alternatively beformed by injection molding.

If the refractive index of the cured resin used to cast the backsubstrate 201 (and hence the surface relief diffractive structure 213)is not substantially matched to the refractive index of theelectro-active material 211, then an in-mold coating step can beemployed. An in-mold coating comprising a material having a desiredrefractive index (e.g., having an index of refraction that issubstantially matched to the index of refraction of the electro-activematerial 211) can be used. The in-mold coating material can be eitherspin coated or dip coated onto the concave surface of a mold to athickness that would fill and planarize the surface relief diffractivestructure 213. This material can then be partially or fully cured on themold using thermal and/or optical means prior to the mold beingassembled with a convex mate.

During the curing of a liquid resin used to form the back substrate 201,the in-mold coating material can adhere itself to the resin. After theresin is cured, the in-mold coating can become integral to the castpart. Further, the in-mold coating can act as a chemical and gas barrierbetween the cured resin forming the back substrate 201 and theelectro-active material 211.

After the resin cure cycle 705, the back substrate 201 can be de-moldedat step 706. At step 706, the molds can also be cleaned for castingsubsequent parts. After the de-molding step 706, the back substrate 201can be edged to a pre-determined diameter at step 707. As stated above,it may be desirable to align the progressive addition optical powerregion 101 to within a desired tolerance with respect to the dynamic,electro-active, diffractive optical power region 102. To increase thelikelihood of proper alignment, the back substrate 201 can be edged suchthat the position of the surface relief diffractive structure 213 isheld to an acceptable tolerance (e.g., +0.25 mm) with respect to theouter edge of the back substrate 201. Alternatively, or in additionthereto, alignment can be achieved optically (e.g., using conventionaloptical alignment mechanisms) using semi-visible alignment marks on eachsubstrate.

During the edging process the bevel structure 215 can be added. Thebevel 215 can be v-shaped and can facilitate the mounting of thesubstrate 201 in various process tooling (e.g., during subsequentsteps). An acceptable or desired tolerance can be achieved by processingthe substrate 201 using, for example, commercially available (CNC)spectacle lens blocking and edging equipment.

Returning to FIG. 5, after the front substrate 202 and the backsubstrate 201 are edged, they can be moved to a clean room (e.g., aclean room of at least class 1000) for steps 502 through 508. At step502, the front substrate 202 and the back substrate 201 can be cleanedand annealed. FIG. 8 provides a flowchart 800 that illustratesoperational steps for cleaning and annealing the front substrate 202 andthe back substrate 201 that is shown more generally as step 502 in FIG.5.

As shown in FIG. 8, cleaning can begin at step 801 with an ultrasonicdetergent wash. An ultrasonic cleaning unit can be used at step 801. Asan example, the cleaning unit can be filled with a detergent such as,for example, Gerber-Coburn FreeWash. The detergent can be diluted withde-ionized (DI) water as per the manufacturer's specification. The washcycle of the cleaning unit can last between 10 and 15 minutes forexample.

After an ultrasonic detergent wash at step 801, the front substrate 202and the back substrate 201 can be moved to a second ultrasonic unit fora rinse cycle at step 802. The rinse cycle can use DI water and can lastbetween 10 and 15 minutes for example. At step 803, the front substrate202 and the back substrate 201 can be further cleaned using anon-ultrasonic rinse. The non-ultrasonic rinse can use DI water and canlast between 15 and 25 minutes for example.

At step 804, the front substrate 202 and the back substrate 201 can bedried with heated, circulated air. The front substrate 202 and the backsubstrate 201 can be dried for approximately 20 minutes for example. Thetemperature of the air for drying can be elevated above ambient toaccelerate drying. However, the temperature of the air can be made tonot exceed the glass transition temperature (T_(g)) of the substratematerial. By way of example only, the T_(g) of Mitsui MR-10 isapproximately 90° C. Accordingly, an appropriate temperature for thecirculated air can be approximately 80° C.

At step 805, the front substrate 202 and the back substrate 201substrates can be moved to a plasma cleaning unit. The front substrate202 and the back substrate 201 substrates can be exposed to an oxygenplasma for between 1 and 3 minutes for example to remove any residualorganic surface contaminants. At step 806, the front substrate 202 andthe back substrate 201 can be subjected to a vacuum anneal. With thevacuum anneal, the front substrate 202 and the back substrate 201 can bethoroughly dried under vacuum and any volatiles can be removed. As withstep 804, the annealing temperature can be kept below the T, of thesubstrate material. Further, the vacuum can be applied for a period oftime sufficient to expel a desired amount of volatiles. By way ofexample only, if Mitsui MR-10 is the substrate material, then a vacuumanneal at 80° C. for at least 24 hours at a pressure below 1 mBar wouldbe desirable.

Returning to FIG. 5, after step 502 is completed, the front substrate202 and the back substrate 201 are ready to receive thin film layersthat enable the dynamic electro-active functionality at step 503. FIG. 9provides a flowchart 900 that illustrates operational steps for applyingthe multiple layers that help form a portion of the dynamic,electro-active, diffractive optical power region 102 that is shown moregenerally as step 503 in FIG. 5. These layers can be applied to theconvex surface of the back substrate 201 and to the concave surface offront substrate 202 (i.e., the mating surfaces) in a symmetrical mannersuch that the description of FIG. 9 can be applicable to both the frontsubstrate 202 and the back substrate 201. Any or all steps illustratedin FIG. 9 can be implemented without exposure to ambient atmosphere(i.e., under vacuum).

As shown in FIG. 9, at step 901, the front substrate 202 and the backsubstrate 201 can be cleaned using an oxygen plasma cleaning. Thecleaning can be implemented, for example, for approximately 1 to 3minutes. At step 902, a first thin film layer (e.g., layers 203 and 204of FIG. 2) can be applied to a substrate. The first thin film layer canbe an insulating material. As an example, the insulating material can beapproximately 20 nm of electrically insulating and substantiallycolorless SiO_(x). The insulating layer can be applied byRadio-Frequency (RF) sputtering a Si target with a mixture of Ar and O₂(e.g., such that the Ar carrier gas sputters Si from the target whichthen reacts with the O₂ gas to form the SiO_(x) oxide to be deposited).

At step 903, the conductive traces can be applied (e.g., the conductivetraces 106 and 107 of FIG. 2). When the substrate is under vacuum, thetraces 106 and 107 can be applied by sputtering a layer of metal (e.g.,Au, Ag, or Al) or transparent conductive oxide (e.g., ITO or ZnO) ontothe first oxide layers 203 and 204 through a shadow mask that definesthe lines as shown in FIG. 1. The thickness of the traces 106 and 107can be larger than 100 nm and, as an example, can be on the order of 1 mto allow for a good connection via the edge.

If the substrates are not under vacuum, then the conductive traces 106and 107 can be made of conductive ink or conductive adhesive that iseither screen printed, ink-jet printed, or stenciled onto the firstoxide layers 203 and 204. The conductive traces 106 and 107 of thepresent invention can also be formed by plating metal onto the firstoxide layers 203 and 204 from an aqueous solution as will be understoodby one having skill in the relevant arts. the conductive traces 106 and107 can be placed in a pre-determined position relative to the semivisible fiducial marks 108 and 109, respectively.

At step 904, transparent conductors (e.g., layers 205 and 206 of FIG. 2)can be applied. The transparent conductors can be ITO and can have athickness, for example, of approximately 20 nm. The transparentconductor layer can be applied by DC sputtering an ITO target with amixture of Ar and 02 such that the Ar carrier gas sputters conductormaterial from the target and the O₂ gas can tune the opticaltransmission and sheet resistivity (Ω/□) of the deposited conductorlayer.

At step 905, the next thin film layer can be applied (e.g., layers 207and 208 of FIG. 2). The next layer can be an insulating layer. As anexample, the insulating material can be electrically insulating andsubstantially colorless SiO_(x) and can have a thickness, for example,of approximately 170 nm. This insulating layer can be applied by RFsputtering a Si target with a mixture of Ar and O₂ (e.g., such that theAr carrier gas sputters Si from the target which then reacts with the O₂gas to form the SiO_(x) oxide to be deposited).

In accordance with an aspect of the present invention, the conductorlayers 205 and 206 can be applied directly onto the first oxide layers203 and 204 prior to applying the conductive traces 106 and 107.Overall, the conductive traces 106 and 107 can be applied before orafter the conductor layers 205 and 206, provided they are formed to bein direct contact with the adjacent conductor layer.

In accordance with an aspect of the present invention, theaforementioned insulating layers 207 and 208 as well as the conductivelayers 205 and 206 can be deposited over the entire area or surface ofthe substrates. In particular, the insulating layers 207 and 208 and theconductive layers 205 and 206 can be deposited without patterning toreduce the visibility of any boundaries or edges. However, to reduce thepossibility of electrical shorting between the front substrate 202 andthe back substrate 201, the conductive layers 205 and 206 can bedeposited using a mask. Alternatively, a portion of the conductivelayers 205 and 206 can be selectively removed after deposition.

FIGS. 10A and 10B illustrates an exemplary deposition of the conductivelayers 205 and 206 in accordance with an aspect of the presentinvention. As shown in FIG. 10A, conductive layer material has not beendeposited over (or has been removed from) areas defined by boundaries1001 and 1002. Accordingly, no conductive path is formed between theconductive traces 106 and 107 to the conductive layer material depositedon the opposite substrate. FIG. 10B illustrates a side view of theEASFLB 100 depicted in FIG. 10A with respect to section A-A′. As shownin FIG. 10B, a region on the back substrate 201 below the conductivetrace 106 is devoid of conductive material. Likewise, a region on thefront substrate 202 above conductive trace 107 is devoid of conductivematerial.

Material 1003 can represent a layer of cured adhesive resin. The curedadhesive resin 1003 can be electrically insulating. However, duringassembly of the EASFLB 100, it may be possible for the front substrate202 and the back substrate 201 to come into contact, thereby resultingin an electrical short. Therefore, the deposition of the conductivelayers 205 and 206 as illustrated in FIGS. 10A and 10B can safeguardagainst this possibility. Further, when the EASFLB 100 is edged to fitinto a spectacle lens frame, the terminating ends of the conductivetraces 106 and 107 can be coated with an additional layer of conductivematerial (e.g., conductive ink or conductive adhesive). By removing theconductive layer material in the regions adjacent to the conductivetraces 106 and 107, the risk of this additional layer of conductivematerial introducing an electrical short between the front substrate 202and the back substrate 201 can be further reduced.

After deposition of the layers 207 and 208, no further inorganiccoatings need to be applied. Accordingly, the surfaces of the layers 207and 208 can be processed to increase their ability to bond with organicfilms and adhesives. Returning to FIG. 5, this is shown as step 504.FIG. 11 provides a flowchart 1100 that illustrates operational steps forapplying an adhesion promoter to the front substrate 202 and the backsubstrate 202 that is shown more generally as step 504 in FIG. 5.

As an example, the layers 207 and 208 can be treated with anorganofunctional silane such as, for example, Dow Corning Z-6030(γ-Methacryloxypropyltrimethoxysilane, CAS #2530-85-0). As will beappreciate by one skilled in the relevant arts, organofunctional silanescan be used to improve the adhesion of organic compounds to inorganicsurfaces.

As shown in FIG. 11, at step 1101, a silane adhesion promoter can beprepared. As an example, the promoter can be an aqueous solution ofapproximately 0.1% to 0.5% silane where the pH of the water has beenadjusted to be in the range of 3.5 to 4.5 with acetic acid before thesilane is added (in accordance with the Dow Corning Z-6030specification).

At step 1102, the layers 207 and 208 can be treated with an oxygenplasma. As an example, the layers 207 and 208 can be treated forapproximately 1 to 3 minutes. At step 1103, the surface of an insulatinglayer can be treated with the silane solution. Application of the silanemixture may be achieved, for example, with a spin processor (i.e., aspin coater). As such, the surface of the insulating layers can beflooded with the silane solution with the processor stationary, allowingit to bond to the plasma treated insulating surface. At step 1104, theexcess solution can be spun off.

At step 1105, any residual silane solution can be washed away in thespin processor using water and/or a solvent (e.g., isopropyl alcohol).At step 1106, the substrate can be dried. The substrate can be dried,for example, under ambient atmosphere for approximately 15 minutes atapproximately 80° C. In accordance with an aspect of the presentinvention, it may be possible to apply the silane in a batch process.With a batch process, several oxygen plasma-treated, ‘insulatinglayer-coated substrates can be loaded into a chamber. The silanematerial can then be put into a vapor phase by means of a heat sourceand/or a vacuum. The silane material can be allowed to bond to theinsulating layer. Such a batch process can greatly improve throughputand potentially eliminate cleaning steps 1104 and 1105 as the surface ofthe insulating layer would only accumulate enough silane material tocover the surface with a molecular monolayer.

Returning to FIG. 5, at step 505, the alignment layers 209 and 210 canbe applied. FIG. 12 provides a flowchart 1200 that illustratesoperational steps for applying the alignment layers 209 and 210 that isshown more generally as step 505 in FIG. 5.

As shown in FIG. 12, at step 1201, the silane-treated insulatingsurfaces (i.e., insulating layers 207 and 208) can be masked off.Physically masking a portion of the insulating layers 207 and 208enables the alignment material to only coat those regions that will bein contact with the electro-active material 211. As an example, theregions within the electro-active material seal feature 103 (as shown inFIG. 1) can be exposed for coating while the remaining portions of theinsulating layers 207 and 208 can be covered or masked to preventexposure. A mask that exhibits poor adhesion to the silane-treatedinsulating surfaces can be used so that the mask can be removed easily.Further, the mask can have good solvent resistance to the solvent fromwhich the alignment layers 209 and 210 can be spin coated (e.g.,Signmask light blue from Avery Dennison).

Once the masks have been applied, at step 1202, the alignment layers 209and 210 can be spin coated from a solution. As an example, the spincoating can be conducted at a speed in the range of 2000 to 4000 rpm forbetween 30 and 90 seconds.

Improved performance of the dynamic, electro-active, diffractive opticalpower region 102 can be achieved, for example, by providing the circularfeatures of the surface relief diffractive structure 213 withrotationally symmetric electro-active material 211 alignment.Accordingly, an aspect of the present invention contemplates the use ofalignment materials such that the alignment direction can be determinedby exposing the material to linearly polarized ultraviolet radiation asdescribed in U.S. patent application Ser. No. 12/101,264, filed Apr. 11,2008, which is hereby incorporated by reference in its entirety.Materials that can be optically processed are available from Elsicon,Inc. (Delaware, USA) and Rolic Technologies Ltd. (Switzerland).

At step 1203, the physical mask can be removed. At step 1204, the coatedsubstrate (e.g., the substrate 201 and/or 202) can be heated to driveoff excess solvent. As an example, the substrates can be heated toapproximately 50° C. under ambient atmosphere for approximately 15minutes.

Returning to FIG. 5, at step 506, the electro-active material 211 can beformulated. Step 506 can be the final step before assembly of the EASFLB100 (i.e., before the substrates 201 and 202 are brought together). FIG.13 provides a flowchart 1300 that illustrates operational steps forformulating the electro-active material 211 that is shown more generallyas step 506 in FIG. 5.

The electro-active material 211 can be a cholesteric liquid crystalline(CLC) material. The CLC material can be a mixture of a nematic liquidcrystal (NLC) with a chiral dopant (CD) as described U.S. applicationSer. No. 12/018,048 filed on Jan. 22, 2008, which is hereby incorporatedby reference in its entirety. At step 1301, a selected NLC can be mixedwith a selected CD. As an example, the NLC can be a material such asBL093 or MDA-98-1602 (Merck) and the CD can be a material such asZLI-4571 or MJ092239 (Merck). Empirical studies by the inventors haveshown that a mixture of NLC with 2.25 wt. % CD gives favorable resultsin terms of achieving low diffraction efficiency when the dynamic,electro-active, diffractive optical power region 102 is not active andfast switching speeds when the dynamic, electro-active, diffractiveoptical power region 102 transitions from an active to an inactivestate.

At step 1302, the electro-active material mixture 211 can be physicallymixed. As an example, the mixing process can be undertaken for a minimumof 12 hours at a temperature above the clearing temperature of the neatNLC. Since the clearing temperature of MDA-98-1602 is 109° C., anytemperature greater than approximately 112° C. can generally be used.

At step 1304, the electro-active material mixture 211 can be degassed.As an example, degassing of the mixture can be undertaken at ambient(i.e., room) temperature and reduced pressure (on the order of 10 mBaror less) for at least 12 hours. The electro-active material mixture 211can be mixed or otherwise agitated during the degassing process toincrease the efficiency of gas removal.

Returning to FIG. 5, steps 507 and 508 represent the final processesapplied to the substrates 201 and 202—i.e., assembly of the substrates201 and 202 with the electro-active material 211 to form the EASFLB 100.To ensure desirable operation of the dynamic, electro-active,diffractive optical power region 102 by way of its correct orientationwith respect to the progressive optical power region 101, the positionof the center of the surface relief diffractive structure 213 withrespect to the progressive optical power region 101 can be determinedand fixed throughout steps 507 and 508.

As described above, when the front substrate 202 is edged (e.g., in step609 of FIG. 6) the position of the progressive optical power region 101can be fixed with respect to the edge of the front substrate 202 towithin a known tolerance. Further, when the back substrate 201 is edged(e.g., in step 707 of FIG. 7) the center of the surface reliefdiffractive structure 213 can be fixed with respect to the edge of theback substrate 201 to within a known tolerance. As a result of thesesteps, alignment of the surface relief diffractive structure 213 withrespect to the progressive optical power region 101 can be accomplishedby a simple rotation of the substrates 201 and 202.

FIG. 14 illustrates an exemplary process for aligning the frontsubstrate 202 and the back substrate 201. FIG. 14A illustrates a frontsubstrate 202. FIG. 14B illustrates a back substrate 201. FIG. 14Cillustrates the front substrate 201 of FIG. 14A placed on top of theback substrate 201 of FIG. 14B. As shown in FIG. 14C, the front and backsubstrates 201 and 202 can be concentric. However, as further shown inFIG. 14C, the front substrate 202 has been rotated slightly clockwisefrom its orientation as shown in FIG. 14A. Additionally, the backsubstrate 201 has been rotated slightly counter-clockwise from itsorientation as shown in FIG. 14B. Consequently, the progressive opticalpower region 101 and the dynamic, electro-active, diffractive opticalpower region 102 are misaligned as shown in FIG. 14C. Further, thealignment of the front substrate 202 and the back substrate 201 aremisaligned.

To properly align the progressive optical power region 101 and thedynamic, electro-active, diffractive optical power region 102 (and toproperly align the front substrate 202 and the back substrate 201), thefront and back substrates 201 and 202 can be rotated while maintainingtheir concentricity. Specifically, the front and back substrates 201 and202 can be rotated such that the semi-visible fiducial marks 108 and 109are aligned as shown in FIG. 1. When the semi-visible fiducial marks 108and 109 are properly aligned, then the center of the surface reliefdiffractive structure 213 will be in proper alignment with respect tothe progressive optical power region 101, as shown in FIG. 14D.

To provide proper alignment between the front substrate 202 and the backsubstrate 201, the front and back substrates 201 and 202 can be mountedin carriers. The carriers can allow the substrates 201 and 202 to bekept concentric, to be rotated about their centers to the point wherethey are in the correct orientation, and to be locked in place (e.g., tolock in a desired orientation or alignment). These carriers may then beloaded into other process tools to aid the completion of other alignmentcritical steps.

FIGS. 15A-D illustrate an exemplary carrier 1500 for holding a substrateof the EASFLB 100. FIG. 15A illustrates a top view of the carrier 1500.FIG. 15B illustrates a bottom view of the carrier 1500. The carrier 1500can comprise fixed, raised portions 1501 and an adjustable raisedportion 1502. The fixed, raised portions 1501 and the adjustable raisedportion 1502 can each have a recess 1503 (shown in FIGS. 15C and 15D) toaccept a beveled edge of a substrate. Adjustable raised portion 1502 canbe positioned between additional fixed, raised portions 1504. The fixed,raised portions 1504 can contain a means for translating the adjustableraised portion 1502 such as, for example, linear bearings.

FIG. 15C illustrates a first cross sectional view of the carrier 1500.Specifically, FIG. 15C illustrates a view across cross section B-B′shownin FIG. 15A. FIG. 15D illustrates a second cross sectional view of thecarrier 1500. Specifically, FIG. 15D illustrates a view across crosssection C-C′ shown in FIG. 15A. Details of the recess 1503 can be seenin the cross sectional views provided by FIGS. 15C and 15D.

A substrate can be held in place by its bevel (e.g., the bevel 214 or215 as shown in FIG. 2) in recesses 1503. Positive pressure from therecesses 1503 can be maintained by the adjustable raised portion 1502which can be, for example, allowed to slide on spring loaded linearbearings contained, for example, within other fixed, raised portions1504. Alignment of the carrier 1500 within other process tooling may beaccomplished through a hole and dowel or kinematic mounting means. Thecarrier 1500 may be outfitted with holes 1505 designed to fit overdowels in a processing tool, for example. The carrier 1500 can also benested within another, similar carrier or in a process tool mount bymeans of a small ledge 1506 produced by reducing the diameter of thelower portion of the carrier 1500.

Completing step 507 depicted in FIG. 5 can begin with mounting the frontand back substrates 201 and 202 within the aforementioned carriers 1500.FIG. 16 provides a flowchart 1600 that illustrates operational steps forexposing the alignment layers 209 and 210 to ultra-violet light that isshown more generally as step 507 in FIG. 5.

At step 1601, the front and back substrates 201 and 202 can be mountedwithin the aforementioned carriers 1500. To do so, the adjustable raisedportion 1502 of a carrier 1500 can be retracted to allow a substrate tobe loaded. At step 1602, a carrier 1500 can be mounted in an opticalalignment tool. The optical alignment tool can include an electronicvision system that locates the semi-visible fiducial marks (e.g., thefiducial marks 108 and/or 109). At step 1603, one or more of thesubstrates can be rotated until a desired orientation between thesubstrates is achieved. Once a substrate is properly oriented, theadjustable raised portion 1502 of the carrier 1500 can come into contactwith the substrate, effectively locking it in place.

At step 1604, the carriers 1500 for the front and back substrates 201and 202 can be loaded into a tool for exposing the alignment layers 209and 210 to linearly polarized UV radiation. At step 1605, the alignmentlayers 209 and 210 can be exposed to polarized UV radiation. As anexample, the alignment layers 209 and 210 can be exposed to polarized UVradiation through a wedge-shaped shadow mask to achieve eitherperpendicular or piecewise perpendicular alignment as described in U.S.patent application Ser. No. 12/101,264, filed Apr. 11, 2008, which ishereby incorporated by reference in its entirety.

The alignment layers 209 and 210 can be processed such that the pre-tiltangle of the electro-active material 211 can be between and 10° and 20°with respect to the surface of the front and back substrates 201 and202. As an example, the alignment material ROP-103 (Rolic TechnologiesLtd.) may be processed to achieve these results by exposing the materialto 80 mJ/cm² of 365 nm UV radiation from a Hamamatsu LC8 lamp at adirection of 40° from the substrate surface normal. As per the ROP-103specification, the radiation from said lamp can be passed through a UVCcut-off filter (Schott WG295) and UV bandpass filter (Schott UG11)before being polarized by means of a wire-grid polarizer (Moxtek).

FIG. 17 provides a flowchart 1700 that illustrates operational steps forassembling the front and back substrates 201 and 202 to form the EASFLB100 that is shown more generally as step 508 in FIG. 5. At step 1701, aportion of the mixed and degassed electro-active material mixture 211 isdispensed onto the surface relief diffractive structure 213. Theelectro-active material mixture 211 can be dispensed by pipette.

FIG. 18A illustrates a close-up view of the electro-active materialmixture 211 (shown in FIG. 18A as element 1802) being dispensed onto theback substrate 201. As shown in FIG. 18A, the back substrate 201 can beloaded and aligned in a back substrate carrier 1801. The amount ofelectro-active material mixture 1802 dispensed can be greater than thefinal volume of electro-active material 211 that can be used tocompletely fill the surface relief diffractive structure 213. By way ofexample only, empirical studies by the inventors have shown thatapproximately 20 μL of the electro-active mixture is sufficient to fillan elliptically shaped surface relief diffractive structure that isapproximately 22 mm wide, 14 mm tall and 3.3 μm deep.

At step 1702, a front substrate 202 loaded and aligned in a frontsubstrate carrier 1803 can be placed in initial contact with a carriermounted back substrate 201. The initial contact between the front andback substrates 201 and 202 can be considered to be a soft assembly. Thesoft assembly of the front and back substrates 201 and 202 described instep 1702 is shown in FIG. 18B.

As shown in FIG. 18B, the front substrate 202 can be positioned within afront substrate carrier 1803. The two carriers 1801 and 1803 can benested together and, as an example, can be aligned with respect to eachother by dowels (not illustrated) in the back substrate carrier 1801that fit into holes in the front substrate carrier 1803.

Steps 1701 and 1702 can be completed in a vacuum. If a vacuum is notused, then after step 1702, the soft assembly of the front and backsubstrates 201 and 202 shown in FIG. 18B can be degassed at step 1703before proceeding with further assembly steps.

At step 1704, the soft assembly can be loaded into a press (not shown).The soft assembly can be loaded into the press such that the frontsubstrate 202 is brought into contact with the back substrate 201. As anexample, the press can be equipped with a pneumatically actuated pistonfor the purpose of bringing the front substrate 202 into contact withthe back substrate 201. FIG. 18C illustrates the front substrate 202being brought into contact with the back substrate 201.

At step 1705, a conformal compression pad can be placed over an areaoverlapping with the surface relief diffractive structure 213 as shownin FIG. 18C. Specifically, prior to applying pressure to the assembly, afirst conformal pad 1804 can be placed on the front substrate 201 overthe area of the surface relief diffractive structure 213. Further, asecond conformal pad 1805 can be placed under the back substrate 201 tosupport the entire assembly. The conformal pad 1804 can be the shape ofthe surface relief diffractive structure 213 (e.g., elliptical). Theconformal pad 1804 can also be slightly larger than the surface reliefdiffractive structure 213 such that it overhangs the electro-activematerial 211 seal feature 103 by approximately 1 mm on all sides asshown in FIG. 18C.

At step 1706, compressed air can be applied to the pneumatic piston.Applying compressed air to the pneumatic piston can bring the front andback substrates 201 and 202 into contact as shown in FIG. 18C. As shownin FIG. 18C, pressure can be applied to the conformal pad 1804. As anexample, empirical studies by the inventors have shown that using apiston with a diameter of approximately 32 mm, with applied compressedair at a pressure of approximately 1 Bar, can achieve contact betweenthe two substrates using an approximately 24 mm wide and 16 mm tallelliptically shaped conformal pad 1804 designed for an ellipticallyshaped surface relief diffractive structure approximately 22 mm wide and14 mm tall. In addition to applying a force to the conformal pad 1804,additional force 1806 can be applied via a second piston and a thirdconformal pad (neither shown) ‘in the region above the adhesive sealfeature 105.

When the two substrates 201 and 202 are in contact, the electro-activematerial seal feature 103 and the adhesive seal feature 105 can betouching the concave, posterior surface of the front substrate 202. Atthis point, a desirable volume of electro-active material 211 has beenfixed by trapping the dispensed electro-active material 1802 between thesurface relief diffractive structure 213 and the front substrate 202.Further, the adhesive cavity 301 can be defined. However, as shown inFIG. 18C, the adhesive cavity can be partially filled with excesselectro-active material mixture 1802 expelled from the surface reliefdiffractive structure 213 during step 1706.

According to an aspect of the present invention, a radius of curvatureof the front substrate 202 can be formed to be slightly larger than aradius of curvature of the back substrate 201. By forming the frontsubstrate 202 to have a radius of curvature that is slightly larger thana predetermined design value (e.g., substantially equal to the radius ofcurvature of the back substrate 201), excess liquid crystal material1802 can be efficiently expelled from the surface relief diffractivestructure 213 during step 1706. Further, by forming the front substrate202 to have a radius of curvature that is slightly larger than a radiusof curvature of the back substrate 201, the amount of air or air bubblestrapped within the desired volume of electro-active material 211 can beminimized or substantially removed.

FIG. 19 illustrates the radius of curvature of the front substrate 202in more detail. As shown in FIG. 19, curve 1901 represents the concave,posterior surface of the front substrate 202 having a radius ofcurvature designed such that during assembly the surface comes intocontact with the apex points of the electro-active material seal feature103 and the adhesive seal feature 105 substantially simultaneously. Thecurve 1901 can represent a radius of curvature that is substantiallyequal to the radius of curvature of the back substrate 201.

In contrast to the curve 1901, the actual radius of curvature of thefront substrate 202 can be slightly larger than this value (as shown bythe solid line representing the concave, posterior surface of the frontsubstrate 202 in FIG. 19). When the actual radius of curvature of thefront substrate 202 is slightly larger than the value represented by thecurve 1901, then the concave, posterior surface 304 can contactdispensed electro-active material 211 at the center of the surfacerelief diffractive structure 213 first as pressure is applied via apneumatic piston (i.e., prior to the concave, posterior surface 304contacting the adhesive seal feature 105). In doing so, excess dispensedelectro-active material 1802 can be expelled outward (i.e., from acenter to the peripheries of the surface relief diffractive structure213) as further pressure is applied.

The benefits of such an approach to assembling the EASFLB 100 arenumerous. First, the concave, posterior surface 304 of the frontsubstrate 202 can expel most, if not all, of the excess dispensedelectro-active mixture 1802 before the concave, posterior surface 304 ofthe front substrate 202 comes into contact with the electro-activematerial seal feature 103.

This can mitigate the risk of entrapping air bubbles within the desiredentrapped volume of electro-active material 211 positioned as desiredover the surface relief diffractive structure 213. Second, this approachcan mitigate the risk of not expelling enough of the excess dispensedelectro-active material 1802.

Empirical studies by the ‘inventors have shown that increasing theradius of curvature of the front substrate 202 by a little as 2 mm, forexample, can result in a significant reduction in entrapped air withinthe volume of electro-active material 211. To implement this approach,extra force may be required to have the concave, posterior surface 304of the front substrate 202 come into contact with adhesive seal feature105 on the back substrate 201.

Returning to FIG. 17, steps 1707 through 1715 represent the next majorsteps in the assembly process. Specifically, steps 1707 through 1715describe a process for removing excess dispensed electro-active materialmixture 1802 from the adhesive cavity 301 and replacing it with anadhesive resin.

At step 1707, a waste collection reservoir can be connected to one ofthe fill ports 104. At step 1708, a supply of cleaning solvent can beconnected to the other fill port 104. FIG. 20A illustrates a supply ofcleaning solvent or a waste collection reservoir being connected to afill port 104. Specifically, FIG. 20A shows tubing 2001 being adhered toa fill port 104 using a UV cure adhesive or adhesive pad 2002.

At step 1709, a solvent (e.g., acetone) can be flushed though theadhesive cavity 301. The solvent can be dispensed through tubing 2001using a fluid dispensing system such as, for example, the dispensingsystem available from Engineered Fluid Dispensing (EFD). As will beunderstood by one skilled in the relevant arts, the solvent can bedispensed through the tubing 2001 to expel any excess electro-activematerial 1802 from the adhesive cavity 301. In particular, the solventcan push the excess electro-active material 1802 into the wastereservoir connected to the other fill port 104.

Once the excess electro-active material 1802 is sufficiently flushed, atstep 1710, the fluid dispensing system can be disconnected from tubing2001. Further, at step 1710, the source of cleaning solvent can bereplaced with a source of clean, dry, compressed air or other inert gas.At step 1711, the selected gas can be flushed through the adhesivecavity 301 to remove excess solvent introduced from step 1709.

At step 1712, the source of clean, dry, compressed air or other inertgas can be disconnected from the tubing 2001. Further, at step 1712, asecond fluid dispensing system for dispensing adhesive resin 1003 can beconnected to the tubing 2001. At step 1713, the adhesive cavity 301 canbe filled with a selective adhesive resin 1003. The adhesive cavity 301can be filled with the adhesive resin 1003 under pressure. FIG. 20Billustrates the adhesive resin 1003 from the tubing 2001 filling theadhesive cavity 301.

The refractive index of the adhesive resin 1003 in a cured state cansubstantially match the refractive index of the material used togenerate the back substrate 201. As an example, if the back substrate201 comprises Mistsui MR-10 with a refractive index of 1.67, then therefractive index of the adhesive resin 1003 in a cured state can varyfrom this value by less than 0.04. In general, any optically clearadhesive resin that can bond the front substrate 202 and the backsubstrate 201 can be used. For example, OP-21 (Dymax) with a refractiveindex of 1.505 in a cured state can be used. Further, the OP-21 resincan be dispensed with a compressed air actuated dispensing syringeequipped with a 23 gauge (0.013″ inner diameter) dispensing needle (notshown) connected to the tubing 2001. For a dispensing syringe with aplunger approximately 22 mm in diameter, compressed air at a pressurebetween 0.3 and 1.0 Bar is sufficient to fill the adhesive cavity 301with the OP-21 resin. To accelerate the resin filling process, vacuummay be applied to the fill port 104 not connected to the fluiddispensing system supplying the resin.

At steps 1714 and 1715, the waste collection reservoir and the fluiddispensing system for dispensing the adhesive resin 1003 can beexchanged. Further, the adhesive resin 1003 can be flushed through theadhesive cavity 301 in the reverse direction. Implementing steps 1714and 1715 can increase the likelihood that the adhesive cavity 301 isuniformly filled with the adhesive resin 1003. In accordance with anaspect of the present invention, the adhesive resin 1003 can be used toflush the excess dispensed electro-active material mixture 1802 from theadhesive cavity 301 such that steps 1708-1711 can be eliminated.

At step 1716, once the adhesive cavity 301 is substantially filled, theadhesive resin 1003 can be cured. In doing so, the front substrate 202and the back substrate 201 can be adhered together. FIG. 20C shows thefront substrate 202 and the back substrate 201 adhered together and theadhesive resin 1003 being cured.

The adhesive 1003 can be cured using ultraviolet and/or visible light2003. The adhesive 1003 can also be cured with heat, or a combination ofheat and optical radiation. As an example, for OP-21 adhesive, cure maybe achieved by exposing the resin to the output of a BlueWave 50 curinglamp for approximately 1.5 minutes through the front substrate 202. Tocure the adhesive 1003 using optical radiation, then at least one of thefront and back substrates 201 and 202 can be at least partiallytransparent to the wavelength(s) required to cure the resin.

At step 1717, after the adhesive 1003 has cured, pressure can be removedfrom the pneumatic piston and the assembled EASFLB 100 can be removedfrom the carriers 1801 and 1803.

The aforementioned process(es) enable the fabrication of anelectro-active lens having an improved liquid crystal seal feature. Inparticular, the positioning of the electro-active material seal feature103 and the manner in which liquid crystal is encapsulated therein (andremoved from the adhesive cavity 301) ensure the manufacture of a viablelens having robust structural integrity and reduced visibility of theelectro-active material seal feature 103. Visibility of theelectro-active material seal feature 103 can be further reduced bymatching an index of refraction of the material used to form theelectro-active material seal feature 103 with an index of refraction ofthe electro-active material 211 and/or the index of refraction of othercomponents of the EASFLB 100.

According to an aspect of the present invention, the electro-activematerial 211 can be dispensed onto the front substrate 202 duringassembly of the EASFLB 100. Consequently, the back substrate 201 can bepositioned over the front substrate 202 for soft assembly of the EASFLB100 and during subsequent assembly steps.

The aforementioned process(es) for fabricating the EASFLB 100 caninclude multiple steps that may be accomplished manually or in asemi-automated or fully-automated manner. In a fully automated systemfor example, a human technician may only be required to load substratesinto racks or to perform other handling prior to the cleaning at step502. Robotic equipment could then move substrates through all theremaining processing steps, with each processing step carried out by adedicated piece of equipment for example. At points in the process wherealignment of the substrates is desired, the robotic equipment can workin conjunction with machine vision systems and other substratemanipulation means (e.g., multi-axis linear and rotational motorizedtranslation stages) to achieve proper alignment. In a semi-automatedprocess for example, human technicians may be required to transfersubstrates between processing steps and/or load substrates into piecesof equipment. Each processing step, however, could be automated in thatit the pieces of equipment would require little or no input from a humantechnician to complete its task.

In accordance with an aspect of the present invention, an electro-activelens of the present invention can comprise two or more substrates.Further, in accordance with an aspect of the present invention, anelectro-active lens of the present invention can comprise substratesarranged or configured in a manner that is different from theconfiguration shown in FIG. 3 for example.

FIG. 21 illustrates a first exemplary alternative electro-activesemi-finished lens blank (EASFLB) 2100 in accordance with an aspect ofthe present invention. As shown in FIG. 21, the EASFLB 2100 can comprisea back substrate 2101, a front substrate 2103, and an intermediatesubstrate 2102. Both the back substrate 2101 and the intermediatesubstrate 2102 can comprise surface relief diffractive structures 2114and 2115, electro-active material seal features 2106 and 2107, andadhesive seal features 2104 and 2105, respectively. The EASFLB 2100 cancomprise a first volume of electro-active material 2110 and a secondvolume of electro-active material 2111. The EASFLB 2100 can alsocomprise a first volume of adhesive material 2112 and a second volume ofadhesive material 2113. The first volume of adhesive material 2112 canbe added via fill ports 2108. The second volume of adhesive material2113 can be added via fill ports 2109.

As shown in FIG. 21 for the EASFLB 2100 (and as shown in FIG. 3 for theEASFLB 100), physical sealing features for containing the electro-activematerial and the adhesive material—as well as surface relief diffractivestructures—are shown as formed on the convex surfaces of constituentsubstrates. However, in accordance with an aspect of the presentinvention and as will be understood by one skilled in the relevant arts,these features can be formed on corresponding concave surfaces of one ormore constituent substrates.

FIG. 22 illustrates a second exemplary alternative electro-activesemi-finished lens blank (EASFLB) 2200 in accordance with an aspect ofthe present invention. As shown in the FIG. 22, the EASFLB 2200 cancomprise a back substrate 2201. The back substrate 2201 can comprise asurface relief diffractive structure 2206 and an electro-active materialseal feature 2204. Electro-active material 2203 can be encapsulatedbetween the surface relief diffractive structure 2206, theelectro-active material seal feature 2204, and a thin substrate 2202.The convex surfaces of the back substrate 2201 and thin substrate 2202can be overmolded with optical material 2205. Optical material 2205 cancomprise a third, pre-fabricated substrate adhered in place or,alternatively, can be formed using a layer of liquid resin cured insitu.

The EASFLB 2200 can be assembled without the use of an adhesive sealfeature (e.g., the adhesive seal feature 103 of the EASFLB 100).However, in accordance with an aspect of the present invention and aswill be understood by one skilled in the relevant arts, an adhesive sealfeature can be ‘included in the EASFLB 2200. For example, an adhesiveseal feature may be useful for setting a desired distance between thesubstrates 2201 and 2202 and a concave surface of a mold used whencuring a layer of liquid resin to form layer 2205.

FIG. 23 illustrates a third exemplary alternative electro-activesemi-finished lens blank (EASFLB) 2300 in accordance with an aspect ofthe present invention. As shown in FIG. 23, the EASFLB 2300 can compriseaback substrate 2301 and a front substrate 2302. The back substrate 2301can comprise a surface relief diffractive structure 2308, anelectro-active material seal feature 2306 and an adhesive seal feature2307. The front substrate 2302 can comprise fill ports 2303. The EASFLB2300 can largely be assembled in a manner similar to that describe abovefor the EASFLB 100. In particular, liquid adhesive resin can be used tofill adhesive cavity 2304 via fill ports 2303. However, the liquidadhesive resin can fill the adhesive cavity 2304 prior to dispensingelectro-active material. Specifically, a desired volume ofelectro-active material 2305 can be added via one or more electro-activematerial fill ports 2306 in the back substrate 2301 after the front andback substrates 2301 and 2302 have been adhered together.

Adding the electro-active material 2305 can be done under pressure. Forexample, the electro-active material 2305 can be added in a mannersimilar to how adhesive resin is added to fill the adhesive cavity 2304(e.g., as described in relation to the EASFLB 100 described above). Theelectro-active material 2305 can also be added via a vacuum fillingmethod. In particular, the EASFLB 2300 can be placed in a vacuumchamber, the chamber can be evacuated and, while still under vacuum, avolume of electro-active material 2305 can be placed over each of thefill ports 2308 on the concave surface of the back substrate 2301.Pressure in the vacuum chamber can then be brought up to ambientpressure. The pressure differential between the ambient and the spaceabove the surface relief diffractive structure 2308 can cause theelectro-active material 2305 to flow into and fill a desired volumeabove the surface relief diffractive structure 2308. Once the desiredvolume has been substantially filled, the electro-active material fillports 2308 can be cleaned of excess electro-active material andsubsequently sealed with a suitable optical material (e.g., a UV curableindex matching resin).

Once assembled, an electro-active lens of the present invention (e.g.,the EASFLB 100, 2100, 2200 or 2300—for simplicity, EASFLB 100 will beused as an exemplary design in the following discussion) can be furtherprocessed. Returning to FIG. 5, further processing of the EASFLB 100 isillustrated as step 509. At step 509, a diameter of the EASFLB can bereduced to expose the conductive traces 106 and 107. Further, step 509can include evaluating the cosmetics of the EASFLB 100 andcharacterizing the optical, electro-active, and electrical performanceof the EASFLB 100.

FIG. 24 provides a flowchart 2400 that illustrates operational steps forfinal processing of the EASFLB 100 in accordance with an aspect of thepresent invention that is shown more generally as step 509 in FIG. 5. AnEASFLB 100 can be examined for its suitability for sale by implementingthe steps of FIG. 24. Further, an EASFLB 100 that fails any of the stepsillustrated in FIG. 24 can be considered to be of a quality not suitedfor dispensing to a user.

At step 2401, a cribbing process can be implemented. The cribbingprocess of step 2401 can reduce the diameter of the EASFLB 100 toestablish a new peripheral edge of the EASFLB 100. The cribbing processcan be accomplished with a machine specifically designed for cribbingspectacle lens blanks or with conventional spectacle lens edgingequipment as will be understood by one skilled in the relevant arts. Byreducing the diameter of the EASFLB 100, the conductive traces 106 and107 can be exposed and can be made accessible via the edge of the EASFLB100. Further, reducing the diameter of the EASFLB 100 can remove thefill ports 104 and the adhesive seal feature 105.

FIG. 25 illustrates the placement of a new peripheral edge 2501 of theEASFLB 100 prior to cribbing. As shown in FIG. 25, the placement of thenew peripheral edge 2501 can expose the conductive traces 106 and 107and can remove lens material comprising the fill ports 104 and theadhesive seal feature 105.

FIG. 26A illustrates the EASFLB 100 having a reduced diameter (i.e., acribbed EASFLB 100). As shown in FIG. 26A, the conductive traces extendto the new peripheral edge 2501. The new peripheral edge 2501 is shownin FIG. 26A to be concentric with the original diameter (not shown) ofthe EASFLB 100 but is not so limited. That is, the new peripheral edge2501 can introduce a new center of the EASFLB 100 that differs from anoriginal center of the EASFLB 100 (i.e., prior to cribbing). As will beappreciated by one skilled in the relevant arts, cribbing semi-finishedlens blanks such that a horizontal and/or vertical offset resultsbetween the center of the article and the center of a new peripheraledge is routinely used to generate semi-finished lens blanks optimizedfor making into spectacle lenses for either the right or left eye of apatient.

At step 2402, conductive material can be applied to the peripheral edgeof the EASFLB 100 at the point(s) where the conductive traces 106 and107 are exposed as a result of the cribbing process of step 2401. Theconductive material can be a conductive paint, ink, or adhesive.Applying the conductive material at step 2402 can facilitate electricalconnection at the edge of the EASFLB 100 via blunt contact pins orconductive elastomer pads for activation of dynamic, electro-active,diffractive optical power region 102.

FIG. 26B illustrates a side view of the EASFLB 100 depicted in FIG. 26A.As shown in FIG. 26B, conductive material 2601 can be applied over theexposed conductive trace 106-B and conductive material 2602 can beapplied over the exposed conductive trace 106-B.

After step 2402, inspection and characterization of the cribbed EASFLB100 can be implemented. At step 2403, a cosmetic inspection can beimplemented. The cosmetic inspection can include an inspection to revealcosmetic flaws introduced during the assembly process. Flaws that cancause an article to be rejected include, but are not limited to,scratches and digs, excessive tinting from the internal coating layers(e.g., ITO), incomplete removal of the dispensed electro-active material1802 from outside the electro-active seal feature 103 and poorly alignedelectro-active material 211 within the dynamic, electro-active,diffractive optical power region 102.

At step 2404, the optical characteristics of the dynamic,electro-active, diffractive optical power region 102 can be tested andcharacterized. In this step, the manufactured article can becharacterized in terms of its diffraction efficiency (activated anddeactivated states), optical power, haze, clarity, transmission,switching and clearing times (described below) and alignment withrespect to the progressive optical power region 101, for example.

At step 2405, the electrical characteristics of the dynamic,electro-active, diffractive optical power region 102 can be tested andcharacterized. In this step, the article can be characterized for itsparallel resistance, series resistance, and capacitance in both theactivated and deactivated states. Articles that pass tests andinspections implemented in steps 2403 through 2405 can then beconsidered suitable for dispensing to a user. For example, at step 2406,an article that meets the quality requirements verified in steps 2403through 2405 can be shipped to a customer.

The EASFLB 100 can be further processed into a finished spectacle lens.Specifically, the EASFLB 100 can be modified to meet the optical powerrequirements of a specific user and can be edged in a manner suitablefor mounting in a spectacle frame. The spectacle frame can be equippedwith corresponding electronics for governing operation of the dynamic,electro-active, diffractive optical power region 102.

As a first step, a specific user's distance vision prescription can beformed into the back surface of the EASFLB 100. The user's distanceprescription can be formed into the back surface using known methodsincluding conventional grinding and polishing or digital surfacing andpolishing (i.e., free forming). When a user's distance prescription isformed into the back surface of the EASFLB 100, the EASFLB 100 can beconsidered to be an electro-active finished lens blank or EASFLB inaccordance with an aspect of the present invention.

In accordance with an aspect of the previous invention (and as describedpreviously), the convex surface of the front substrate 202 of the EASFLB100 may not comprise the progressive optical power region 101. Instead,a progressive optical power region 101 can be introduced on the backsurface of the EASFLB 100 via free forming (e.g., along with the user'sdistance vision prescription) as will be appreciated by one skilled inthe relevant arts. Further, in accordance with an aspect of the presentinvention, the EASFLB 100 can include a first progressive optical powerregion on a front surface of the EASFLB 100 (e.g., formed by mold or byfree-forming) and a second progressive optical power region formed on aback surface of the EASFLB 100 (e.g., formed by mold or byfree-forming).

After surfacing and polishing the posterior surface of EASFLB 100 toform an EASFLB in accordance with the present invention, both surfacesof the EASFLB can receive a series of coatings including, but notlimited to, scratch resistance coatings, anti-reflection coatings,anti-soiling coatings and cushion coatings, for example.

The surfaced, polished, and coated EASFLB 100—as an EASFLB—cansubsequently be edged to fit into a spectacle frame. FIG. 27 illustratesa top view of a cribbed, surfaced, and coated EASFLB 100. An outline2701 illustrates the perimeter of an edged spectacle lens for the righteye of a user that can be formed from the cribbed, surfaced and coatedEASFLB 100. As shown in FIG. 27, a portion of the conductive traces106-A and 107-A can remain after edging to allow electrical connectionto the dynamic, electro-active, diffractive optical power region 102. Incontrast, the conductive traces 106-B and 107-B can be completelyremoved.

Note that the cribbed, surfaced, and coated EASFLB 100 can be edged foreither a right-eye or a left-eye lens since conductive traces 106 and107 (shown as conductive traces 106-A, 106-B, 107-A and 107-B) can bepositioned on each side of the EASFLB 100 during assembly. However, inaccordance with an aspect of the present invention, the EASFLB 100 canbe assembled with only one set of conductive traces (i.e., with eithertraces 106-A and 107-A only or with traces 106-B and 107-B only). Whenassembled as such, the EASFLB 100 can be fabricated for edging as aright-eye lens or a left-eye lens exclusively, depending upon which pairof traces are included in the EASFLB 100 and which pair of traces areomitted during assembly.

The cribbed, surfaced, and coated EASFLB 100 depicted in FIG. 27 can beedged using standard spectacle lens edging equipment. During edging, theedge of the lens can be ground, polished, beveled or grooved, forexample, and the lens may also be drilled to allow for a rimless or3-piece spectacle frame.

FIG. 28 shows a finished, edged spectacle lens 2700 of the presentinvention. The finished spectacle lens 2700 can comprise a perimeter2701 and can be generated from the initially assembled EASFLB 100. Afteredging, as was similarly described in step 2402 of flowchart 2400 inFIG. 24, a conductive paint, ink, or adhesive can be applied to theperipheral edge of the finished lens 2700 at the point(s) where theconductive traces 106-A and 107-A are exposed during the edging process.As described previously, applying the conductive material in this mannercan facilitate electrical connection at the edge of the lens 2700 viablunt contact pins or conductive elastomer pads for activation ofdynamic, electro-active, diffractive optical power region 102.

In accordance with an aspect of the present invention, the transparentconductors 206 and 207 can be electrically connected to a controller(not shown) via the electrical conductive traces 106 and 107. Thecontroller can be located on a frame holding or containing an EASFLB 100that has been processed to fit the frame (e.g., the finished lens 2800).The controller can apply voltages to the transparent conductors 206 and207 predetermined to cause an electric field to form across theelectro-active material 211 as well as the alignment layers 209 and 210.The electric field can change the orientation of the molecules of theelectro-active material 211, thereby changing the refractive index ofthe electro-active material 211.

The change in refractive index of the electro-active material 211contained within the dynamic, electro-active, diffractive optical powerregion 102 of the EASFLB 100 is predetermined to cause a change inoptical power via modulation of diffraction efficiency. When no voltageis applied to the conductors 206 and 207, the refractive index of theelectro-active material 211 can match the refractive index of thesurface relief diffractive structures 213. Accordingly, no optical phasedelay is generated and no light is focused (i.e., the diffractionefficiency at the designed focal length or corresponding optical poweris zero). When a predetermined voltage is applied to the conductors 206and 207, the refractive index of the electro-active material 211 can bedifferent from the refractive index of the surface relief diffractivestructures 213. Accordingly, an optical phase delay is generated forfocusing approximately all incident light to the designed optical power(i.e., approximately 100% diffraction efficiency at the design focallength or corresponding optical power). Thus, by switching the voltageapplied to the conductors 206 and 207 on or off, the optical power ofthe electro-active element of the EASFLB 100 is likewise switched on oroff, thereby modulating the diffraction efficiency of the electro-activeelement between maximum and minimum values, respectively.

As shown in FIG. 2, the dynamic, electro-active, diffractive opticalpower region 102 is in optical communication with the progressiveaddition optical power region 101. The progressive addition opticalpower region 101 can provide a user with an optical power that is lessthan the user's total needed near distance optical power correction. Thedynamic, electro-active, diffractive optical power region 102 can alsoprovide an optical power (e.g., when turned on) that is less that theuser's total needed near distance optical power correction. When used incombination, however, the optical power provided by the dynamic,electro-active, diffractive optical power region 102 can be combinedwith the optical power provided by the progressive addition opticalpower region 101 to provide a combined optical power that issubstantially equal to the user's total needed near distance opticalpower correction. As such, the progressive addition optical power region101 can be considered as providing a first incremental add power and thedynamic, electro-active, diffractive optical power region 102 can beconsidered as providing a second incremental add power. Accordingly, thefirst and second ‘incremental add powers can together sum to the user'stotal needed near distance optical power. Overall, the first incrementaladd power can be any portion or fraction of the user's total needed neardistance optical power and the second incremental add power can be anycomplementing portion.

Using the dynamic, electro-active, diffractive optical power region 102to supplement the optical power of the progressive addition opticalpower region 101 can reduce the overall optical power that is to beprovided by the progressive addition optical power region 101. Sinceunwanted astigmatism from a progressive addition optical power region isknown to increases at a greater than linear rate as a function of thetotal add power of a progressive addition region, supplementing theoptical power of the progressive addition optical power region 101reduces these astigmatic and other unwanted effects, such as, forexample, distortion, perceptual blur, and swim.

The EASFLB 100 (and consequently the finished lens 2800) can compriseone or more vision zones. For example, the EASFLB 100 can comprise adistance vision zone, one or more intermediate vision zones, and a nearvision zone. The near vision zone can be formed by the overlapping nearadd power region of the progressive addition optical power region 101 incombination with the optical power provided by the dynamic,electro-active, diffractive optical power region 102. The one or moreintermediate vision zones can be formed by the overlapping non-near addpower regions of the progressive addition optical power region 101 incombination with the optical power provided by the dynamic,electro-active, diffractive optical power region 102. The distancevision zone can be formed by optical power provided by the frontsubstrate 202 and the back substrate 201 (e.g., such that neither theprogressive addition optical power region 101 nor the dynamic,electro-active, diffractive optical power region 102 contributes to theoptical power of the distance vision zone).

The EASFLB 100 can be fabricated to only include the dynamic,electro-active, diffractive optical power region 102. One or moreprogressive addition optical power regions can then be added duringsubsequent processing and finishing of the EASFLB 100. For example, oneor more progressive addition optical regions can be added byfree-forming. Additionally, the EASFLB 100 can be fabricated with anelectro-active element having a Fresnel structure.

As previously mentioned, a controller can be used to activate anddeactivate the dynamic, electro-active, diffractive optical power region102. The time that elapses between switching the dynamic,electro-active, diffractive optical power region 102 from an off-stateto an on-state and from an on-state to an off-state can be considered tobe the switch times of the dynamic, electro-active, diffractive opticalpower region 102 (or the switch time of the EASFLB 100/finished lens2800 more generally). The off-state to on-state switch time can differfrom the on-state to off-state switch time. In the off-state, thedynamic, electro-active, diffractive optical power region 102 can beconsidered as providing a first optical power value and/or a firstdiffraction efficiency value. In the on-state, the dynamic,electro-active, diffractive optical power region 102 can be consideredas providing a second optical power value and/or a second diffractionefficiency value. The on-state to off-state switching time can includethe time that elapses before the dynamic, electro-active, diffractiveoptical power region 102 is substantially free of any haze (e.g., domaindisclinations).

The intrinsic response time of the molecules of the electro-activematerial 211 to the application and removal of a voltage waveform andthe clearing time of domain disclinations (e.g., haze) formed during theswitching process can largely determine the switching speed of thedynamic, electro-active, diffractive optical power region 102. Theintrinsic response time of the electro-active material 211 and theclearing time of domain disclinations are not necessarily additive(i.e., these times can run or occur in parallel).

Factors that can influence switching speed can include the RC timeconstant of the dynamic, electro-active, diffractive optical powerregion 102, the viscosity of the selected electro-active material 211,the concentration of any chiral dopant, the thickness of the layer ofelectro-active material 211, and the pre-tilt angle of theelectro-active material 211. The capacitance of the dynamic,electro-active, diffractive optical power region 102 can be determinedby the dielectric constant of the electro-active material 211. Theresistance of the dynamic, electro-active, diffractive optical powerregion 102 can be determined by the resistance of the conductors 206 and207, the resistance of conductive traces 106 and 107, resistances due toelectrical interconnects and resistances internal to the electronicsused to activate the lenses.

According to an aspect of the present invention, the pre-tilt angle ofthe electro-active material 211 can be between and 10° and 20° withrespect to the surface of the front substrate 202 and the back substrate201. As discussed above, the alignment material (e.g., the alignmentlayers 209 and 210) can be processed to achieve these desired results.The thickness of the electro-active material 211 can be the dominatefactor in determining switch speed as, generally, the intrinsic responsetime of the electro-active material 211 molecules and the clearing timeare approximately quadratic with thickness.

A portion of the dynamic, electro-active, diffractive optical powerregion 102 is shown in FIG. 29. As shown in FIG. 29, the total thicknessof the electro-active material 211 is shown as “d.” This total thicknesscan be the sum of the depth, “d₁”, of the surface relief diffractivestructures 213 and any gap, “d₂”, between the peaks of the surfacerelief diffractive structures 213 and the alignment layer 209 (not shownin FIG. 29). As an example, the depth d₁ of the surface reliefdiffractive structures 213 can be approximately 3.3 μm and the extra gapd₂ can be kept to be 1 μm or less (e.g., zero).

To switch from the off-state to the on-state, a voltage waveform can beapplied as described previously. As an example, the voltage waveform canbe a zero DC bias square wave with a frequency between 20 Hz and 100 Hzand a peak-to-peak voltage between 10 volts and 30 volts. Based on theabove exemplary designed depths, the contributions to switching time dueto the intrinsic response time of the electro-active material 211molecules and the clearing time of domain disclinations can both be lessthan 100 ms (0.1 s). This can yield a total switching time of less thanapproximately 100 ms. This result can be achieved in accordance with anaspect of the present invention where the depth d₁ of the surface reliefdiffractive structures 213 is approximately 3.3 μm and theelectro-active material 211 is 1VIDA-98-1602 with 2.25 wt. % ZLI-4571.

To switch from the on-state to the off-state, the voltage waveform canbe removed and the conductors 206 and 207 can be electrically shortedvia the drive electronics to dissipate stored electrical charge. Underthis scenario, the intrinsic response time of the molecules of theelectro-active material 211 to the removal of the voltage waveform canstill be less than 100 ms. However, the clearing time of domaindisclinations may be longer (generally due to no applied voltage drivingthe electro-active material 211) and is generally the limiting factorthat determines the on-state to off-state switching time. This clearingtime can depend strongly on the thickness, d, of the electro-activematerial 211 and the concentration of chiral dopant in theelectro-active material 211. According to an aspect of the presentinvention, the clearing time may be kept shorter than approximately 250ms by keeping the depth of the surface relief diffractive structures d₁less than 3.3 μm (generally less than 4.0 μm) and the concentration ofchiral dopant less than 2.5 wt. %.

The clearing time can be decreased by reducing the depth of the surfacerelief diffractive structures 213 (i.e., by reducing di depicted in FIG.29). Methods for reducing the depth of the surface relief diffractivestructures 213 can include smoothing discontinuities and sloping sidewalls comprising the surface relief diffractive structure 213 asdescribed in U.S. patent application Ser. No. 12/054,313, filed on Mar.24, 2008, which is hereby incorporated by reference in its entirety.

FIG. 30A illustrates an exemplary, ideal surface relief diffractivestructure 3001 having a local grating period Λ and a depth d₁. The idealsurface relief diffractive structure 3001 can theoretically provide 100%diffraction efficiency. The ideal surface relief diffractive structure3001 comprises discontinuities that cause optical scatter due to poorliquid crystal alignment at these discontinuities. By smoothing thesediscontinuities, and by further sloping the vertical side walls of theideal surface relief diffractive structure 2001, liquid crystalalignment can be improved and optical scatter can be reduced.

FIG. 30B illustrates a smoothed surface relief diffractive structure3002 having smoothed discontinuities and sloped vertical side walls. Thesmoothed surface relief diffractive structure 3002 can exhibit improvedliquid crystal alignment and reduced optical scatter with respect to thestructure depicted in FIG. 30A. The improved performance is obtained ata slight cost to diffraction efficiency due to the region of width 8which introduces a non-ideal phase profile. However, this smoothing canreduce the depth from di to d₁′. As a result, clearing time can bereduced. FIG. 30C illustrates the ideal surface relief diffractivestructure 3001 in comparison to the smoothed surface relief diffractivestructure 3002 to clearly illustrate the differences in each designapproach.

FIG. 31A illustrates a second smoothed surface relief diffractivestructure 3102. With respect to the first smoothed surface reliefdiffractive structure 3002, the degree of smoothing and/or sloping ofside walls of the second smoothed surface relief diffractive structure3102 can be reduced and flat regions 3103 can be introduced in thetroughs of the surface relief profile.

FIG. 31B illustrates the ideal surface relief diffractive structure 3001in comparison to the smoothed surface relief diffractive structure 3102to clearly illustrate the differences in each design approach. For thesurface relief diffractive structures depicted in FIGS. 30 and 31,d₁″<d₁′<d₁. As a result, the surface relief diffractive structure 3102can lead to an even further decrease in switching and clearing time.Further, δ′>δ for the surface relief diffractive structures depicted inFIGS. 30 and 31 (i.e., the width of the region of non-ideal phaseprofile is larger for the surface relief diffractive structure 3102 incomparison to the surface relief diffractive structure 3002). Overall,however, the decrease in diffraction efficiency experienced by thesurface relief diffractive structure 3102 can be less than the decreasein diffraction efficiency experienced by the surface relief diffractivestructure 3002.

CONCLUSION

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample and not limitation. It will be apparent to one skilled in thepertinent art(s) that various changes in form and detail can be madetherein without departing from the spirit and scope of the invention.Therefore, the present invention should only be defined in accordancewith the following claims and their equivalents.

Overall, the present invention can be embodied as an unfinished lensblank, a semi-finished lens blank, a finished lens blank, an edged lens,a contact lens, an intra-ocular lens, a corneal inlay or a cornealonlay.

The invention is not limited to the operational descriptions provided bythe included flowcharts. Rather, it will be apparent to persons skilledin the relevant art(s) from the teachings herein that other operationalcontrol flows are within the scope and spirit of the present invention.Control steps can be added or eliminated as will be understood by oneskilled in the relevant art(s).

What is claimed is:
 1. An electro-active lens comprising: a frontsubstrate; a back substrate bonded to the front substrate by anadhesive; an electro-active element disposed between the front substrateand the back substrate; and a cribbed peripheral edge, the cribbedperipheral edge extending across the front substrate, the adhesive, andthe back substrate.
 2. The electro-active lens of claim 1, furthercomprising at least one conductive trace in electrical communicationwith the electro-active element.
 3. The electro-active lens of claim 2,wherein a portion of at least one conductive trace is exposed on thecribbed peripheral edge.
 4. The electro-active lens of claim 1, furthercomprising a plurality of conductive traces, each conductive trace beingin electrical communication with the electro-active element.
 5. Theelectro-active lens of claim 4, wherein a portion of each conductivetrace is exposed on the cribbed peripheral edge.
 6. The electro-activelens of claim 2, further comprising at least one conductive contactdisposed on the cribbed peripheral edge, the at least one conductivecontact being in electrical communication with at least one conductivetrace.
 7. The electro-active lens of claim 4, further comprising aplurality of conductive contacts disposed on the cribbed peripheraledge, each conductive contact being in electrical communication with atleast one conductive trace.
 8. The electro-active lens of claim 1,wherein the electro-active lens is a semi-finished lens blank.
 9. Theelectro-active lens of claim 1, wherein the electro-active lens is afinished lens.
 10. A pair of eyeglasses comprising: at least oneelectro-active lens of claim
 1. 11. A method of making an electro-activelens comprising: cribbing the peripheral edge of an electro-active lens,the electro-active lens comprising: a front substrate; a back substratebonded to the front substrate; and an electro-active element disposedbetween the front substrate and the back substrate; wherein the cribbedperipheral edge is defined by at least the front substrate and the backsubstrate; and wherein the peripheral edge is cribbed after theelectro-active element is disposed between the front substrate and theback substrate.
 12. The method of claim 11, wherein the electro-activelens further comprises at least one conductive trace in electricalcommunication with the electro-active element.
 13. The method of claim12, wherein the cribbing of the peripheral edge of the electro-activelens removes at least a portion of at least one conductive trace,thereby exposing the at least one conductive trace.
 14. The method ofclaim 11, wherein the electro-active lens further comprises a pluralityof conductive traces, each conductive trace being in electricalcommunication with the electro-active element.
 15. The method claim 14,wherein the cribbing of the peripheral edge of the electro-active lensremoves at least a portion of at least one conductive trace, therebyexposing at least one conductive trace.
 16. The method claim 14, whereinthe cribbing of the peripheral edge of the electro-active lenscompletely removes at least one conductive trace.
 17. The method ofclaim 12, further comprising disposing at least one conductive contacton the cribbed peripheral edge, the at least one conductive contactbeing in electrical communication with at least one conductive trace.18. The method of claim 14, further comprising disposing a plurality ofconductive contacts on the cribbed peripheral edge, each conductivecontact being in electrical communication with at least one conductivetrace.
 19. The method of claim 11, wherein the electro-active lens is asemi-finished lens blank.
 20. The method of claim 11, further comprisingedging the cribbed peripheral edge to form a finished lens.